How Much Ballast to Achieve Upward Acceleration?

[WhoCares357]

Homework Statement

A research balloon of total mass 305 kg is descending vertically with a downward acceleration of 1.4 m/s2. How much ballast must be thrown from the car to give the balloon an upward acceleration equal to 1.3 m/s2, presuming that the upward lift of the balloon does not change.

Homework Equations

$$F=ma$$

The Attempt at a Solution

I'm having trouble because the original acceleration is positive and the final one is positive. How do I set up the proportion with what I have? Setting $$-305*1.4=m_2*1.3$$ doesn't work.

 

[rl.bhat]

What is the acceleration of the freely falling balloon?
why the balloon's acceleration is reduced?
What is the net acceleration of the balloon when it is moving up?